DUA Polling Reconfiguration (Windows Embedded Standard 2009)


The HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DUAgent\Parameters\Config\PollToD registry key for the day of the week and the hour of the day is required for polling. It specifies to Duagent.exe when to start polling for a specified update program (.dup) file. You can provide up to seven structures of type REG_BINARY and you must specify at least one. Each structure contains 32 bits representing the days of the week and the hours of the day to poll for a .dup file. For example, if you provide one structure set to 0Xffffffff, Duagent.exe polls for the specified .dup file every day of the week at every hour of the day. If you provide a structure set to 0X20400000, Duagent.exe polls every Monday at 1 A.M. The following illustration shows this concept.

You must specify at least one DWORD to indicate when to start polling for a .dup file, but you can specify up to seven DWORD values for increased polling resolution.

The HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DUAgent\Parameters\Config\PollInterval registry key for the polling interval is required for polling and specifies the polling frequency during the indicated day of the week and hour of the day. For example, if you have configured Duagent.exe to start polling on Sunday at 11 P.M. by setting bits 30 and 0, the polling occurs during the 11 P.M. to 12 P.M. hour at a frequency specified by the polling interval.

The PollInterval value is a DWORD of type REG_DWORD, specified in seconds. For example, a value of 0x012C polls every 300 seconds during the defined poll day and hour.

Once Duagent.exe has polled, located, and updated the device by using the commands found in the .dup file, the file is removed from the device and the device is not updated again. Successive polls for the .dup file at the specified polling interval during the specified day of the week and hour of the day fail to find the file. However, if the device polls from a remote location by using HTTP, the .dup is not deleted and is executed on successive polls.

The HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DUAgent\Parameters\Config\PollJitter registry key for poll jitter is optional and is used to randomly distribute polls within the specified poll interval. Duagent.exe only polls once within the specified poll interval. The PollJitter value of type REG_DWORD is interpreted as a flag, either on or off.

To enable poll jitter, you must provide a DWORD set to 1. The jitter can be disabled by setting the DWORD to 0.

If poll jitter is not configured, Duagent.exe polls exactly on the specified PollInterval. If Duagent.exe has not polled when a poll window (the day and hour) passes, Device Update Agent polls after the window has passed.

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